Method and apparatus for attaching tissue to bone, including the provision and use of a novel knotless suture anchor system

ABSTRACT

Apparatus for securing a suture to a bone, the apparatus comprising an elongated body having a distal end, a proximal end, and a lumen extending between the distal and proximal ends, the lumen comprising a distal section and a proximal section, the distal section having a wider diameter than the proximal section; an elongated element extending through the lumen; and a locking element mounted to the distal end of the elongated element and disposed in the distal section of the lumen; whereby, when the elongated body is disposed in bone, and a suture extends through at least a portion of the lumen, and the locking element is thereafter moved proximally, proximal movement of the locking element causes the elongated body to capture the suture to the elongated body, whereby to secure the suture to the bone.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

This patent application is a continuation of pending prior U.S. patentapplication Ser. No. 13/830,501, filed Mar. 14, 2013 by Pivot Medical,Inc. for METHOD AND APPARATUS FOR ATTACHING TISSUE TO BONE, INCLUDINGTHE PROVISION AND USE OF A NOVEL KNOTLESS SUTURE ANCHOR SYSTEM, which:

(i) is a continuation-in-part of pending prior U.S. patent applicationSer. No. 13/642,168, filed Dec. 26, 2012 by Chris Pamichev et al. forMETHOD AND APPARATUS FOR RE-ATTACHING THE LABRUM TO THE ACETABULUM,INCLUDING THE PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM, whichpatent application in turn claims benefit of:

-   -   (a) prior International (PCT) Patent Application No.        PCT/US2011/021173, filed Jan. 13, 2011 by Pivot Medical, Inc.        and Chris Pamichev et al. for METHOD AND APPARATUS FOR        RE-ATTACHING THE LABRUM TO THE ACETABULUM, INCLUDING THE        PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM, which in        turn:        -   (i) claims benefit of prior U.S. Provisional Patent            Application Ser. No. 61/326,709, filed Apr. 22, 2010 by            Chris Pamichev et al. for METHOD AND APPARATUS FOR            RE-SECURING THE LABRUM TO THE ACETABULUM, INCLUDING THE            PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM; and        -   (ii) is a continuation-in-part of pending prior U.S. patent            application Ser. No. 12/839,246, filed Jul. 19, 2010 by            Chris Pamichev et al. for METHOD AND APPARATUS FOR            RE-ATTACHING THE LABRUM TO THE ACETABULUM, INCLUDING THE            PROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM, which in            turn claims benefit of:            -   (1) prior U.S. Provisional Patent Application Ser. No.                61/271,205, filed Jul. 17, 2009 by Chris Pamichev et al.                for METHOD AND APPARATUS FOR RE-SECURING THE LABRUM TO                THE ACETABULUM, INCLUDING THE PROVISION AND USE OF A                NOVEL NANO TACK SYSTEM; and            -   (2) prior U.S. Provisional Patent Application Ser. No.                61/326,709, filed Apr. 22, 2010 by Chris Pamichev et al.                for METHOD AND APPARATUS FOR RE-SECURING THE LABRUM TO                THE ACETABULUM, INCLUDING THE PROVISION AND USE OF A                NOVEL SUTURE ANCHOR SYSTEM;

(ii) is a continuation-in-part of prior U.S. patent application Ser. No.13/538,378, filed Jun. 29, 2012 by Andrew Lantz et al. for METHOD ANDAPPARATUS FOR RE-ATTACHING THE LABRUM TO THE ACETABULUM, INCLUDING THEPROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM, which patentapplication in turn claims benefit of prior U.S. Provisional PatentApplication Ser. No. 61/502,621, filed Jun. 29, 2011 by Andrew Lantz etal. for FORCE-LIMITING (FORCE-CONTROLLING) DELIVERY MECHANISMS FOR THECONTROLLED DELIVERY OF THE SUTURE ANCHOR; and

(iii) claims benefit of prior U.S. Provisional Patent Application Ser.No. 61/644,129, filed May 8, 2012 by Jeremy Graul et al. for METHOD ANDAPPARATUS FOR RE-ATTACHING THE LABRUM TO THE ACETABULUM, INCLUDING THEPROVISION AND USE OF A NOVEL SUTURE ANCHOR SYSTEM; and

(iv) claims benefit of prior U.S. Provisional Patent Application Ser.No. 61/718,997, filed Oct 26, 2012 by Pivot Medical, Inc. and JeremyGraul et al. for METHOD AND APPARATUS FOR RE-ATTACHING THE LABRUM TO THEACETABULUM, INCLUDING THE PROVISION AND USE OF A NOVEL SUTURE ANCHORSYSTEM.

The above-identified patent applications are hereby incorporated hereinby reference.

FIELD OF THE INVENTION

This invention relates to surgical methods and apparatus in general, andmore particularly to surgical methods and apparatus for treating a hipjoint and other anatomy.

BACKGROUND OF THE INVENTION The Hip Joint in General

The hip joint is a ball-and-socket joint which movably connects the legto the torso. The hip joint is capable of a wide range of differentmotions, e.g., flexion and extension, abduction and adduction, medialand lateral rotation, etc. See FIGS. 1A, 1B, 1C and 1D.

With the possible exception of the shoulder joint, the hip joint isperhaps the most mobile joint in the body. Significantly, and unlike theshoulder joint, the hip joint carries substantial weight loads duringmost of the day, in both static (e.g., standing and sitting) and dynamic(e.g., walking and running) conditions.

The hip joint is susceptible to a number of different pathologies. Thesepathologies can have both congenital and injury-related origins. In somecases, the pathology can be substantial at the outset. In other cases,the pathology may be minor at the outset but, if left untreated, mayworsen over time. More particularly, in many cases, an existingpathology may be exacerbated by the dynamic nature of the hip joint andthe substantial weight loads imposed on the hip joint.

The pathology may, either initially or thereafter, significantlyinterfere with patient comfort and lifestyle. In some cases, thepathology can be so severe as to require partial or total hipreplacement. A number of procedures have been developed for treating hippathologies short of partial or total hip replacement, but theseprocedures are generally limited in scope due to the significantdifficulties associated with treating the hip joint.

A better understanding of various hip joint pathologies, and also thecurrent limitations associated with their treatment, can be gained froma more thorough understanding of the anatomy of the hip joint.

Anatomy of the Hip Joint

The hip joint is formed at the junction of the leg and the torso. Moreparticularly, and looking now at FIG. 2, the head of the femur isreceived in the acetabular cup of the hip, with a plurality of ligamentsand other soft tissue serving to hold the bones in articulatingrelation.

More particularly, and looking now at FIG. 3, the femur is generallycharacterized by an elongated body terminating, at its top end, in anangled neck which supports a hemispherical head (also sometimes referredto as “the ball”). As seen in FIGS. 3 and 4, a large projection known asthe greater trochanter protrudes laterally and posteriorly from theelongated body adjacent to the neck of the femur. A second, somewhatsmaller projection known as the lesser trochanter protrudes medially andposteriorly from the elongated body adjacent to the neck. Anintertrochanteric crest (FIGS. 3 and 4) extends along the periphery ofthe femur, between the greater trochanter and the lesser trochanter.

Looking next at FIG. 5, the hip socket is made up of three constituentbones: the ilium, the ischium and the pubis. These three bones cooperatewith one another (they typically ossify into a single “hip bone”structure by the age of 25 or so) in order to collectively form theacetabular cup. The acetabular cup receives the head of the femur.

Both the head of the femur and the acetabular cup are covered with alayer of articular cartilage which protects the underlying bone andfacilitates motion. See FIG. 6.

Various ligaments and soft tissue serve to hold the ball of the femur inplace within the acetabular cup. More particularly, and looking now atFIGS. 7 and 8, the ligamentum teres extends between the ball of thefemur and the base of the acetabular cup. As seen in FIGS. 8 and 9, alabrum is disposed about the perimeter of the acetabular cup. The labrumserves to increase the depth of the acetabular cup and effectivelyestablishes a suction seal between the ball of the femur and the rim ofthe acetabular cup, thereby helping to hold the head of the femur in theacetabular cup. In addition to the foregoing, and looking now at FIG.10, a fibrous capsule extends between the neck of the femur and the rimof the acetabular cup, effectively sealing off the ball-and-socketmembers of the hip joint from the remainder of the body. The foregoingstructures (i.e., the ligamentum teres, the labrum and the fibrouscapsule) are encompassed and reinforced by a set of three main ligaments(i.e., the iliofemoral ligament, the ischiofemoral ligament and thepubofemoral ligament) which extend between the femur and the perimeterof the hip socket. See, for example, FIGS. 11 and 12, which show theiliofemoral ligament, with FIG. 11 being an anterior view and FIG. 12being a posterior view.

Pathologies of the Hip Joint

As noted above, the hip joint is susceptible to a number of differentpathologies. These pathologies can have both congenital andinjury-related origins.

By way of example but not limitation, one important type of congenitalpathology of the hip joint involves impingement between the neck of thefemur and the rim of the acetabular cup. In some cases, and looking nowat FIG. 13, this impingement can occur due to irregularities in thegeometry of the femur. This type of impingement is sometimes referred toas cam-type femoroacetabular impingement (i.e., cam-type FAI). In othercases, and looking now at FIG. 14, the impingement can occur due toirregularities in the geometry of the acetabular cup. This latter typeof impingement is sometimes referred to as pincer-type femoroacetabularimpingement (i.e., pincer-type FAI). Impingement can result in a reducedrange of motion, substantial pain and, in some cases, significantdeterioration of the hip joint.

By way of further example but not limitation, another important type ofcongenital pathology of the hip joint involves defects in the articularsurface of the ball and/or the articular surface of the acetabular cup.Defects of this type sometimes start out fairly small but often increasein size over time, generally due to the dynamic nature of the hip jointand also due to the weight-bearing nature of the hip joint. Articulardefects can result in substantial pain, induce and/or exacerbatearthritic conditions and, in some cases, cause significant deteriorationof the hip joint.

By way of further example but not limitation, one important type ofinjury-related pathology of the hip joint involves trauma to the labrum.More particularly, in many cases, an accident or sports-related injurycan result in the labrum being torn away from the rim of the acetabularcup, typically with a tear running through the body of the labrum. SeeFIG. 15. These types of labral injuries can be very painful for thepatient and, if left untreated, can lead to substantial deterioration ofthe hip joint.

The General Trend Toward Treating Joint Pathologies UsingMinimally-Invasive, and Earlier, Interventions

The current trend in orthopedic surgery is to treat joint pathologiesusing minimally-invasive techniques. Such minimally-invasive, “keyhole”surgeries generally offer numerous advantages over traditional, “open”surgeries, including reduced trauma to tissue, less pain for thepatient, faster recuperation times, etc.

By way of example but not limitation, it is common to re-attachligaments in the shoulder joint using minimally-invasive, “keyhole”techniques which do not require large incisions into the interior of theshoulder joint. By way of further example but not limitation, it iscommon to repair torn meniscal cartilage in the knee joint, and/or toreplace ruptured ACL ligaments in the knee joint, usingminimally-invasive techniques.

While such minimally-invasive approaches can require additional trainingon the part of the surgeon, such procedures generally offer substantialadvantages for the patient and have now become the standard of care formany shoulder joint and knee joint pathologies.

In addition to the foregoing, in view of the inherent advantages andwidespread availability of minimally-invasive approaches for treatingpathologies of the shoulder joint and knee joint, the current trend isto provide such treatment much earlier in the lifecycle of thepathology, so as to address patient pain as soon as possible and so asto minimize any exacerbation of the pathology itself. This is in markedcontrast to traditional surgical practices, which have generallydictated postponing surgical procedures as long as possible so as tospare the patient from the substantial trauma generally associated withinvasive surgery.

Treatment for Pathologies of the Hip Joint

Unfortunately, minimally-invasive treatments for pathologies of the hipjoint have lagged far behind minimally-invasive treatments forpathologies of the shoulder joint and the knee joint. This is generallydue to (i) the constrained geometry of the hip joint itself, and (ii)the nature and location of the pathologies which must typically beaddressed in the hip joint.

More particularly, the hip joint is generally considered to be a “tight”joint, in the sense that there is relatively little room to maneuverwithin the confines of the joint itself. This is in marked contrast tothe shoulder joint and the knee joint, which are generally considered tobe relatively “spacious” joints (at least when compared to the hipjoint). As a result, it is relatively difficult for surgeons to performminimally-invasive procedures on the hip joint.

Furthermore, the pathways for entering the interior of the hip joint(i.e., the natural pathways which exist between adjacent bones and/ordelicate neurovascular structures) are generally much more constrainingfor the hip joint than for the shoulder joint or the knee joint. Thislimited access further complicates effectively performingminimally-invasive procedures on the hip joint.

In addition to the foregoing, the nature and location of the pathologiesof the hip joint also complicate performing minimally-invasiveprocedures on the hip joint. By way of example but not limitation,consider a typical detachment of the labrum in the hip joint. In thissituation, instruments must generally be introduced into the joint spaceusing an angle of approach which is offset from the angle at which theinstrument addresses the tissue. This makes drilling into bone, forexample, significantly more complicated than where the angle of approachis effectively aligned with the angle at which the instrument addressesthe tissue, such as is frequently the case in the shoulder joint.Furthermore, the working space within the hip joint is typicallyextremely limited, further complicating repairs where the angle ofapproach is not aligned with the angle at which the instrument addressesthe tissue.

As a result of the foregoing, minimally-invasive hip joint proceduresare still relatively difficult to perform and hence less common inpractice. Consequently, many patients are forced to manage their hippain for as long as possible, until a resurfacing procedure or a partialor total hip replacement procedure can no longer be avoided. Theseprocedures are generally then performed as a highly-invasive, openprocedure, with all of the disadvantages associated withhighly-invasive, open procedures.

As a result, there is, in general, a pressing need for improved methodsand apparatus for treating pathologies of the hip joint.

Re-Attaching the Labrum of the Hip Joint

As noted above, hip arthroscopy is becoming increasingly more common inthe diagnosis and treatment of various hip pathologies. However, due tothe anatomy of the hip joint and the pathologies associated with thesame, hip arthroscopy is currently practical for only selectedpathologies and, even then, hip arthroscopy has generally met withlimited success.

One procedure which is sometimes attempted arthroscopically relates tothe repair of a torn and/or detached labrum. This procedure may beattempted when the labrum has been damaged but is still sufficientlyhealthy and capable of repair. The repair can occur with a labrum whichis still attached to the acetabulum or after the labrum has beendeliberately detached from the acetabulum (e.g., so as to allow foracetabular rim trimming to treat a pathology such as a pincer-type FAI)and needs to be subsequently re-attached. See, for example, FIG. 16,which shows a normal labrum which has its base securely attached to theacetabulum, and FIG. 17, which shows a portion of the labrum (in thiscase the tip) detached from the acetabulum. In this respect it shouldalso be appreciated that repairing the labrum rather than removing thelabrum is generally desirable, inasmuch as studies have shown thatpatients whose labrum has been repaired tend to have better long-termoutcomes than patients whose labrum has been removed.

Unfortunately, current methods and apparatus for arthroscopicallyrepairing (e.g., re-attaching) the labrum are somewhat problematic. Thepresent invention is intended to improve upon the current approaches forlabrum repair.

More particularly, current approaches for arthroscopically repairing thelabrum typically use apparatus originally designed for use inre-attaching ligaments to bone. For example, one such approach utilizesa screw-type anchor, with two lengths of suture extending therefrom, andinvolves deploying the anchor in the acetabulum above the labrumre-attachment site. After the anchor has been deployed, one length ofsuture is passed either through the detached labrum or, alternatively,around the detached labrum. Then that length of suture is tied to theother length of suture so as to secure the labrum against the acetabularrim. See FIG. 18.

Unfortunately, suture anchors of the sort described above aretraditionally used for re-attaching ligaments to bone and, as a result,tend to be relatively large, since they must carry the substantialpull-out forces normally associated with ligament reconstruction.However, this large anchor size is generally unnecessary for labrumre-attachment, since the labrum is not subjected to substantial forces,and the large anchor size typically causes unnecessary trauma to thepatient.

Furthermore, the large size of traditional suture anchors can beproblematic when the anchors are used for labrum re-attachment, sincethe suture anchors generally require a substantial bone mass for secureanchoring, and such a large bone mass is generally available only asubstantial distance up the acetabular shelf. In addition, the largesize of the suture anchors generally makes it necessary to set thesuture anchor a substantial distance up the acetabular shelf, in orderto ensure that the distal tip of the suture anchor does notinadvertently break through the acetabular shelf and contact thearticulating surfaces of the joint. However, labral re-attachmentutilizing a suture anchor set high up into the acetabular shelf createsa suture path, and hence a labral draw force, which is not directlyaligned with the portion of the acetabular rim where the labrum is to bere-attached. As a result, an “indirect” draw force (also known as“eversion”) is typically applied to the labrum, i.e., the labrum isdrawn around the rim of the acetabulum rather than directly into theacetabulum. See FIG. 18. This can sometimes result in a problematiclabral re-attachment and, ultimately, can lead to a loss of the suctionseal between the labrum and femoral head, which is a desired outcome ofthe labral re-attachment procedure. Using suture anchors of a smallersize allows the suture anchor to be set closer to the rim of theacetabulum, which can help reduce this effect. See FIG. 18A.

In addition to the foregoing, suture anchors of the sort described aboverequire that a knot be tied at the surgical site in order to secure thelabrum to the acetabulum. This can be time-consuming and inconvenient toeffect. More particularly, and as noted above, the suture anchortypically has a suture connected thereto so that two lengths of sutureextend from the suture anchor and are available to secure the labrum tothe acetabulum (which receives the suture anchor). One or both of thetwo lengths of suture are passed through or around the labrum and thenknotted to one another so as to secure the labrum to the acetabulum.However, it can be time-consuming and inconvenient to form the knot atthe surgical site, given the limited access to the surgical site and therestricted work space at the surgical site.

Accordingly, a new approach is needed for arthroscopically re-attachingthe labrum to the acetabulum.

SUMMARY OF THE INVENTION

The present invention provides a novel method and apparatus forre-attaching the labrum to the acetabulum.

Among other things, the present invention provides a novel knotlesssuture anchor system which may be used to re-attach the labrum to theacetabulum, and/or to attach other tissue to bone.

In one preferred form of the present invention, there is provided aknotless suture anchor wherein a loop of suture is passed through thelabrum (or other tissue) and its two free ends are slidably connected(e.g., slidably threaded through) the knotless suture anchor. After theknotless suture anchor is advanced into the acetabulum (or other bone)and the loop of suture is tensioned so as to hold the labrum (or othertissue) in place against the acetabulum (or other bone), the knotlesssuture anchor is reconfigured so as to lock the loop of suture to theknotless suture anchor and hence secure the labrum (or other tissue) tothe acetabulum (or other bone).

In one form of the present invention, there is provided apparatus forsecuring a first object to a second object, the apparatus comprising:

an elongated body having a distal end, a proximal end, and a lumenextending between the distal end and the proximal end, the lumencomprising a distal section and a proximal section, the distal sectionof the lumen having a wider diameter than the proximal section of thelumen;

a window extending through the side wall of the elongated body andcommunicating with the lumen, the window being disposed in the vicinityof the intersection between the distal section of the lumen and theproximal section of the lumen and being sized to receive a first objecttherein;

an elongated element extending through the lumen of the elongated body,the elongated element comprising a proximal end and a distal end; and

a locking element mounted to the distal end of the elongated element anddisposed in the distal section of the lumen;

whereby, when the elongated body is disposed in a second object, and afirst object extends through the window, and the locking element isthereafter moved proximally, proximal movement of the locking elementcauses the elongated body to capture the first object to the elongatedbody, whereby to secure the first object to the second object.

In another form of the present invention, there is provided apparatusfor securing a first object to a second object, the apparatuscomprising:

an elongated body having a distal end, a proximal end, and a lumenextending between the distal end and the proximal end;

a window extending through the side wall of the elongated body andcommunicating with the lumen, the window being sized to receive a firstobject therein;

a locking element disposed in the lumen, the locking element having alarger proximal end and a smaller distal end;

whereby, when the elongated body is disposed in a second object, and afirst object extends through the window, and the locking element isthereafter moved distally, distal movement of the locking elementcaptures the first object to the elongated body, whereby to secure thefirst object to the second object.

In another form of the present invention, there is provided a method forsecuring a first object to a second object, the method comprising:

providing apparatus comprising:

-   -   an elongated body having a distal end, a proximal end, and a        lumen extending between the distal end and the proximal end, the        lumen comprising a distal section and a proximal section, the        distal section of the lumen having a wider diameter than the        proximal section of the lumen;    -   a window extending through the side wall of the elongated body        and communicating with the lumen, the window being disposed in        the vicinity of the intersection between the distal section of        the lumen and the proximal section of the lumen and being sized        to receive a first object therein;    -   an elongated element extending through the lumen of the        elongated body, the elongated element comprising a proximal end        and a distal end; and    -   a locking element mounted to the distal end of the elongated        element and disposed in the distal section of the lumen;

extending the first object through the window;

positioning the elongated body in the second object; and

moving the locking element proximally, such that proximal movement ofthe locking element causes the elongated body to capture the firstobject to the elongated body, whereby to secure the first object to thesecond object.

In another form of the present invention, there is provided a method forsecuring a first object to a second object, the method comprising:

providing apparatus comprising:

-   -   an elongated body having a distal end, a proximal end, and a        lumen extending between the distal end and the proximal end;    -   a window extending through the side wall of the elongated body        and communicating with the lumen, the window being sized to        receive a first object therein;    -   a locking element mounted to the distal end of the elongated        element and disposed in the lumen, the locking element having a        larger proximal end and a smaller distal end;

extending the first object extends through the window;

positioning the elongated body in the second object; and

moving the locking element distally, such that distal movement of thelocking element captures the first object to the elongated body, wherebyto secure the first object to the second object.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention will bemore fully disclosed or rendered obvious by the following detaileddescription of the preferred embodiments of the invention, which is tobe considered together with the accompanying drawings wherein likenumbers refer to like parts, and further wherein:

FIGS. 1A-1D are schematic views showing various aspects of hip motion;

FIG. 2 is a schematic view showing bone structures in the region of thehip joint;

FIG. 3 is a schematic anterior view of the femur;

FIG. 4 is a schematic posterior view of the top end of the femur;

FIG. 5 is a schematic view of the pelvis;

FIGS. 6-12 are schematic views showing bone and soft tissue structuresin the region of the hip joint;

FIG. 13 is a schematic view showing cam-type femoroacetabularimpingement (i.e., cam-type FAI);

FIG. 14 is a schematic view showing pincer-type femoroacetabularimpingement (i.e., pincer-type FAI);

FIG. 15 is a schematic view showing a labral tear;

FIG. 16 is a schematic view showing a normal labrum which has its basesecurely attached to the acetabulum;

FIG. 17 is a schematic view showing a portion of the labrum detachedfrom the acetabulum;

FIG. 18 is a schematic view showing a suture anchor being used tore-attach the labrum to the acetabulum;

FIG. 18A is a schematic view showing another suture anchor being used tore-attach the labrum to the acetabulum;

FIGS. 19 and 20 are schematic views showing a novel knotless sutureanchor system formed in accordance with the present invention;

FIGS. 21-25 are schematic views showing the knotless suture anchor ofthe knotless suture anchor system shown in FIGS. 19 and 20, and thedistal end of the inserter of the knotless suture anchor system shown inFIGS. 19 and 20;

FIGS. 26 and 27 are schematic views showing the handle of the inserterof the knotless suture anchor system shown in FIGS. 19 and 20;

FIG. 28 shows portions of the knotless suture anchor system (i.e., thesuture anchor, inserter and suture threader) shown in FIGS. 19 and 20;

FIGS. 28A, 29 and 30 show a suture loaded into the knotless sutureanchor system shown in FIGS. 19 and 20, wherein FIG. 30 is a cutawayview of FIG. 29;

FIGS. 31-36 are schematic views showing the knotless suture anchor ofthe knotless suture anchor system shown in FIGS. 19 and 20 securing asuture to bone, wherein FIG. 36 is a cutaway view of FIG. 35;

FIGS. 37-47, 47A and 47B are schematic views showing variousconstructions for the locking element of the knotless suture anchorsystem shown in FIGS. 19 and 20;

FIGS. 48-59 are schematic views showing an alternative form of knotlesssuture anchor system formed in accordance with the present invention,wherein FIGS. 48, 49, 52, 54, 55 and 58 comprise side views, and FIGS.50, 51, 53, 56, 57 and 59 comprise top views;

FIGS. 60-63 are schematic views showing the knotless suture anchorsystem of FIGS. 48-59 securing a suture to bone (whereby to secure alabrum to bone);

FIGS. 64-66 are schematic views showing an alternative form of knotlesssuture anchor and the distal end of its associated inserter;

FIGS. 67-69 are schematic views showing another alternative form ofknotless suture anchor;

FIGS. 70 and 71 are schematic views showing another alternative form ofknotless suture anchor and the distal end of its associated inserter;

FIGS. 72-74 are schematic views showing another alternative form ofknotless suture anchor and the distal end of its associated inserter;

FIGS. 75 and 76 are schematic views showing another alternative form ofknotless suture anchor and the distal end of its associated inserter;

FIGS. 77 and 78 are schematic views showing another alternative form ofknotless suture anchor and the distal end of its associated inserter;

FIGS. 79-81 are schematic views showing another alternative form ofknotless suture anchor;

FIGS. 82 and 83 are schematic views showing another alternative form ofknotless suture anchor and the distal end of its associated inserter;

FIGS. 84-86 are schematic views showing another alternative form ofknotless suture anchor; and

FIGS. 87-90 are schematic views showing another alternative form ofknotless suture anchor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Knotless Suture AnchorSystem

Looking first at FIGS. 19 and 20, there is shown a novel knotless sutureanchor system 5 formed in accordance with the present invention.Knotless suture anchor system 5 generally comprises a knotless sutureanchor 10, an inserter 15 for inserting knotless suture anchor 10 inbone, and a suture threader 20 for threading a suture through knotlesssuture anchor 10 (and inserter 15) before the knotless suture anchor isdeployed in bone.

Looking next at FIGS. 21-25, knotless suture anchor 10 generallycomprises a body 25, a locking element 30 for radially expanding thebody and securing a suture (not shown in FIGS. 21-25) to the body, and apull rod 35 for moving locking element 30 proximally relative to body25, whereby to simultaneously (i) radially expand the body so as tosecure knotless suture anchor 10 to bone, and (ii) secure a suture tothe body so as to secure that suture to knotless suture anchor 10 (andhence to the bone within which the knotless suture anchor is secured).

More particularly, and still looking now at FIGS. 21-25, body 25comprises a distal end 40 terminating in a distal end surface 45, aproximal end 50 terminating in a proximal end surface 55, and a steppedbore 60 extending from distal end surface 45 to proximal end surface 55.Stepped bore 60 comprises a distal section 65 having a wider diameter,and a proximal section 70 having a narrower diameter. Distal section 65preferably has a relatively smooth interior wall, and proximal section70 preferably has a textured interior wall, e.g., threads 72. A shoulder75 is formed at the intersection of distal section 65 and proximalsection 70.

Body 25 of knotless suture anchor 10 has a generally cylindrical outersurface 80 which may include ribs (or other bone-engaging elements) 85.Ribs (or other bone-engaging elements) 85 may have variousconfigurations, either identical to or varied from one another, and/ormay be regularly or irregularly spaced, as will hereinafter bediscussed. Body 25 also includes a side opening 90 which extendsradially through the side wall of body 25 so as to connect stepped bore60 with the region outside of the body 25 of knotless suture anchor 10.Side opening 90 is preferably located in the vicinity of shoulder 75. Inone preferred form of the invention, side opening 90 extends from aregion distal to shoulder 75 to a region approximately even with, orproximal to, shoulder 75. A portion of generally cylindrical outersurface 80 is recessed as shown at 95 (i.e., to accommodate a sutureextending alongside the outer surface of the body), and the proximal end50 of body 25 is reduced in diameter as shown at 100 so as to form anannular shoulder 105. Note that the axis of stepped bore 60 isoff-center from the axis of outer surface 80 (FIG. 25) so as tostrengthen the side wall of body 25 at 95 while still minimizing anchordiameter.

Still looking now at FIGS. 21-25, locking element 30 comprises anelongated body 110 having an enlarged distal end 115 which includes athin flange 120 and terminates in a distal end surface 125, a proximalend 130 which terminates in a proximal end surface 135, and a steppedbore 140 which extends from distal end surface 125 to proximal endsurface 135. Note that thing flange 120 has a larger diameter thanenlarged distal end 115, and enlarged distal end 115 has a largerdiameter than the portion of locking element 30 which is proximal toenlarged distal end 115. Proximal end 130 of locking element 30 ispreferably tapered, e.g., in the manner shown in FIGS. 22 and 24,whereby to facilitate advancement of locking element 30 into proximalsection 70 of stepped bore 60 of body 25, as will hereinafter bediscussed. In one form of the present invention, proximal end 130 oflocking element 30 includes a weakened section 132, preferably formed bya circumferential groove 133, whereby to allow the proximalmost portionof locking element 30 to separate from the remainder of locking element30, as will hereinafter be discussed. Stepped bore 140 comprises adistal section 145 and a proximal section 150, with distal section 145having a larger diameter than the diameter of proximal section 150, andwith proximal section 150 having a smaller diameter than the diameter ofdistal section 145. A shoulder 155 is formed at the intersection ofdistal section 145 and proximal section 150. Locking element 30 has agenerally cylindrical outer surface 160 which may include ribs (or othersurface profile elements) 165. Ribs (or other surface profile elements)165 may have various configurations, either identical to or varied fromone another, and/or may be regularly or irregularly spaced, as willhereinafter be discussed.

Locking element 30 is sized so that (i) the diameter of its generallycylindrical outer surface 160 is less than the diameter of distalsection 65 of stepped bore 60 of body 25, and (ii) the diameter of itsflange 120 at the distal end of the locking element is larger than thediameter of distal section 65 of stepped bore 60 of body 25, such thatcylindrical outer surface 160 of locking element 30 can be received indistal section 65 of stepped bore 60 of body 25, but flange 120 at thedistal end of locking element 30 cannot normally be received in distalsection 65 of stepped bore 60 of body 25. Furthermore, locking element30 is sized so that when its flange 120 is seated against end surface 45of body 25, proximal end surface 135 of locking element 30 is disposeddistal to at least the proximalmost portion of side opening 90 in body25 and, preferably, distal to the entire side opening 90 in body 25. Inone preferred form of the invention, the diameter of generallycylindrical outer surface 160 of locking element 30 is approximatelyequal to, or somewhat larger than, the diameter of proximal section 70of stepped bore 60 of body 25. As a result, when one or more sutures aredisposed within distal section 65 of stepped bore 60 (i.e., when one ormore sutures extend through proximal section 70 of stepped bore 60,through distal section 65 of stepped bore 60 and out of side opening 90,as will hereinafter be discussed), proximal movement of locking element30 into proximal section 70 of stepped bore 60 of body 25 simultaneouslycauses (i) the creation of an interference fit between the generallycylindrical outer surface 160 of locking element 30, the one or moresutures extending through proximal section 70 of stepped bore 60 and theinner wall of proximal section 70 of stepped bore 60, and (ii) radialexpansion of body 25. Thus it will be seen that proximal movement oflocking element 30 into proximal section 70 of stepped bore 60 of body25 causes radial expansion of the body so as to secure knotless sutureanchor 10 to a surrounding bone, and captures the suture within theproximal section 70 of stepped bore 60, whereby to secure the suture tothe knotless suture anchor 10 (and hence to the bone within which theknotless suture anchor 10 is secured). Furthermore, distal end 115 oflocking element 30 has a diameter which is smaller than distal section65 of stepped bore 60, but distal end 115 of locking element 30 has adiameter which is larger than proximal section 70 of stepped bore 60. Asa result, distal end 115 of locking element 30 will stop proximalmovement of locking element 30 when distal end 115 abuts shoulder 75 ofbody 25.

It will be appreciated that, when locking element 30 is moved proximallyinto proximal section 70 of stepped bore 60 of body 25, thin flange 120(located at the distal end of locking element 30) will engage distal endsurface 45 of body 25 and thereafter collapse (or bend) so that thinflange 120 is able to enter distal section 65 of stepped bore 60. Byremaining engaged against distal end surface 45 of body 25 until asufficient proximal force is applied to pull rod 35, thin flange 120helps to prevent the unintentional actuation of knotless suture anchor10 by requiring the application of a force to pull rod 35 above apre-determined threshold force (i.e., the pre-determined force at whichthin flange 120 collapses, or bends) in order to permit movement oflocking element 30 proximally (whereby to actuate knotless suture anchor10). Note that thin flange 120 also helps secure knotless suture anchor10 on inserter 15 during delivery of the knotless suture anchor to thesurgical site. This is of significance since, unlike knotted sutureanchors which are typically delivered through a guide which providesmechanical support to the knotted suture anchor during delivery,knotless suture anchors are typically delivered without the benefit ofsuch mechanical support and hence are subjected to more forces which candislodge the knotless suture anchor from the inserter during delivery tothe bone site and into the bone hole.

Looking now at FIGS. 21-27, pull rod 35 comprises an elongated body 170having a distal end 175 terminating in an enlarged head 180, and aproximal end 185 terminating within the handle 190 of inserter 15, aswill hereinafter be discussed in further detail. Elongated body 170 ofpull rod 35 is sized to pass through proximal section 150 of bore 140 oflocking element 30, and enlarged head 180 of pull rod 35 is sized toseat in distal portion 145 of bore 140 of locking element 30, such thatpulling proximally on elongated body 170 of pull rod 35 will causelocking element 30 to move proximally.

It should also be appreciated that enlarged head 180 of pull rod 35comprises a proximal surface 191 which extends circumferentially aroundthe distal end of pull rod 35 at the junction of (or transition between)elongated body 170 and enlarged head 180. Proximal surface 191 ofenlarged head 180 may comprise a fillet or chamfer, such that when asufficient proximal force (i.e., a proximal force above a set thresholdforce) is applied to pull rod 35, enlarged head 180 can move proximallyinto bore 140 of locking element 30, as will hereinafter be discussed.

Looking now at FIGS. 19-27, inserter 15 generally comprises a shaft 195having a distal end 200 terminating in distal end surface 205, aproximal end 210 terminating in a proximal end surface 215, and a bore220 extending therebetween. Distal end 200 of shaft 195 comprises acounterbore 225 which is sized so as to receive the proximal end 50 ofbody 25 of knotless suture anchor 10, in a male/female connection, withdistal end surface 205 of shaft 195 being seated against annularshoulder 105 of body 25. Note that the proximal end 50 of body 25 ofknotless suture anchor 10 is not round (FIG. 25), and the cross-sectionof counterbore 225 is also not round, so as to resist twisting motionsof suture anchor 10 vis-à-vis inserter 15. A side opening 227 extendsradially through the side wall of shaft 195 so as to connect bore 220with the region outside the shaft. Preferably side opening 227 in shaft195 is aligned with side opening 90 in knotless suture anchor 10.

The proximal end 210 of shaft 195 is secured to handle 190. Handle 190comprises a lever 230 which is rotatably mounted to handle 190 via apivot pin 235. The proximal end 185 of pull rod 35 is secured to lever230 such that when lever 230 is activated (i.e. squeezed towards handle190), pull rod 35 is moved proximally, whereby to move locking element30 proximally, as will hereinafter be discussed. A finger-to-fingerengagement is provided at 232, 233 so as to prevent accidentalactivation of lever 230. Preferably pull rod 35 is set with a smallamount of tension (that is below the threshold force that is required toretract locking element 30) so as to help hold suture anchor 10 on thedistal end of inserter 15.

Looking next at FIGS. 19, 20 and 28, suture threader 20 is provided forthreading a suture through knotless suture anchor 10 (and inserter 15)before the knotless suture anchor is deployed in bone. In one preferredform of the invention, suture threader 20 is pre-mounted to shaft 195 ofinserter 15, with the suture threader having a portion threaded throughinserter 15 and knotless suture anchor 10 so as to facilitate threadinga suture (or multiple sutures) through the knotless suture anchor 10 andthrough inserter 15; see FIGS. 19 and 28. More particularly, suturethreader 20 preferably comprises a body 240 having clamping arms 245extending therefrom. Clamping arms 245 are configured to releasablysecure body 240 of suture threader 20 to shaft 195 of inserter 15. Awire shaft 250 extends distally from body 240, and a collapsible,diamond-shaped capture element 255 is secured to the distal end of wireshaft 250. In a preferred embodiment, the wire shaft 250 anddiamond-shaped capture element 255 are formed out of a single, thinNitinol wire having its two terminal ends secured to body 240. Prior touse, suture threader 20 has its diamond-shaped capture element 255collapsed radially inwardly, and it is passed through side opening 227of shaft 195, along bore 220 of shaft 195 of inserter 15, along proximalportion 70 of stepped bore 60 of body 25 of knotless suture anchor 10,and out side opening 90 of body 25 of knotless suture anchor 10,whereupon diamond-shaped capture element 255 re-expands to its erectedshape, e.g., in the manner shown in FIGS. 19 and 28.

Using the Knotless Suture Anchor System to Secure Suture to Bone

In use, the suture which is to be secured to a bone by means of knotlesssuture anchor 10 is first passed through the tissue which is to besecured to the bone, next the suture is passed through diamond-shapedcapture element 255 of suture threader 20, and then suture threader 20is pulled rearwardly on shaft 195 of inserter 15, towing the suture withit, until the suture has been pulled through side opening 90 of knotlesssuture anchor 10, along proximal portion 70 of stepped bore 60 of body25 of knotless suture anchor 10, along bore 220 of shaft 195 of inserter15, and out side opening 227 in shaft 195 of inserter 15. See FIGS. 29and 30, which show an exemplary suture S threaded through body 25 ofknotless suture anchor 10 and shaft 195 of inserter 15. It should beappreciated that, although a single suture strand is depicted in thefigures, in a preferred embodiment, two strands of suture are threadedthrough body 25 of knotless suture anchor 5 and shaft 195 of inserter15.

Thereafter, and looking now at FIGS. 29-36, in order to secure thesuture S to a bone, inserter 15 is used to advance knotless sutureanchor 10 and suture S into a hole H (FIGS. 29 and 30) formed in a boneB. Suture S may then be tensioned so as to adjust the position of thetissue relative to the bone. This can be accomplished by pulling on thefree ends of the suture S, either independently or together. Sufficienttension will overcome any friction in the suture path and reduce thedistance from the tissue to the knotless suture anchor 10 (and hence tothe bone). Then the lever 230 is moved toward handle 190, whereby toforce pull rod 35 proximally. This action causes locking element 30 tomove proximally (FIGS. 31 and 32) so as to simultaneously (i) expandbody 25 of knotless suture anchor 10 within the hole formed in the bone,whereby to secure knotless suture anchor 10 to the bone, and (ii)capture suture S between locking element 30 and the side wall ofproximal portion 70 of stepped bore 60 of body 25 of knotless sutureanchor 10, whereby to secure suture S to body 25 of knotless sutureanchor 10. Further proximal movement of pull rod 35 (by way of movinglever 230 further towards handle 190) causes the enlarged head 180 ofpull rod 35 to force its way through proximal portion 150 of steppedbore 140 of locking element 30 (FIG. 33). It should be appreciated that,in order to impart a sufficient proximal force to locking element 30 soas to move locking element 30 proximally, while still permittingenlarged head 180 to force its way through bore 140 of locking element30 when a sufficient proximal force is applied to pull rod 35, enlargedhead 180 needs to be larger in diameter than the diameter of proximalsection 150 of bore 140 but not so large that it cannot be pulledthrough the bore 140 when sufficient proximal force is applied. It hasbeen found that, with a bore 140 having a diameter of approximately0.0135 inches, an enlarged head 180 having a diameter of approximately0.0250 inches will provide adequate “interference” between enlarged head180 and shoulder 155 so as to provide sufficient resistance to enteringbore 140 when a proximal force less than the maximum proximal force(i.e., partial activation force) is applied (FIG. 32). At the same time,such a configuration permits the enlarged head 180 to enter bore 140(FIG. 33) when a sufficient proximal force (i.e., full activation force)is applied to pull rod 35 (and hence to enlarged head 180).

In other words, with the present invention, the force required to pulllocking element 30 proximally so as to lock suture S to the sutureanchor, and so as to expand the body of the suture anchor, is less thanthe force required to draw pull rod 35 through locking element 30 so asto disengage pull rod 35 from locking element 30—this ensures that pullrod 35 is not disengaged from locking element 30 until locking element30 has locked suture S to the suture anchor and expanded the body of thesuture anchor. Furthermore, the force required to draw pull rod 35through locking element so as to disengage pull rod 35 from lockingelement 30 is less than the force required to pull locking element 30through the proximal end of body 25 of the knotless suture anchor 10(due to the fact that distal end 115 of locking element 30 issufficiently larger than proximal section 150 of bore 140)—this ensuresthat pull rod 35 disengages from locking element 30 and locking element30 is never pulled through the proximal end of body 25 of the knotlesssuture anchor 10. In other words, the force required to pull lockingelement 30 through proximal end of body 25 is greater than the forcerequired to draw pull rod 35 through locking element so as to disengagepull rod 35 from locking element 30 (i.e., the full activation force).

In addition, the shape of proximal surface 191 of enlarged head 180 ofpull rod 35 also influences the proximal force at which enlarged head180 will enter into, and begin moving through, bore 140 in lockingelement 30. In a preferred form of the invention, proximal surface 146of enlarged head 180 comprises a fillet of approximately 0.005 inches(or a chamfer of approximately 45 degrees).

Further proximal movement of pull rod 35 (i.e., by way of moving lever230 even further towards handle 190) causes pull rod 35 to completelypull enlarged head 180 through bore 140 and out of the proximal end oflocking element 30 (FIG. 34).

As noted above, locking element 30 comprises a weakened section 132located at the proximal end of locking element 30. As enlarged head 180encounters weakened section 132, the weakened section will separate fromlocking element 30, allowing a proximal portion of locking element 30 todetach from the locking element and be removed from the anchor by pullrod 35 (FIG. 34). At this point, inserter 15 can be removed from thehole H in bone B (see FIGS. 35 and 36), leaving the knotless sutureanchor 10 secured in the hole H in the bone B, and with the suture Ssecured to the knotless suture anchor and emanating from the bone holeH, whereby to secure the suture (and hence the tissue which the suture Shas been passed through) to the bone B.

Additional Constructions

It should be appreciated that ribs 165 of locking element 30, and theinternal threads 72 disposed on the interior wall of the proximalsection 70 of stepped bore 60, provide greater securement to oneanother, and to suture S, than that which would be provided by smoothsurfaces. Capturing suture S between the ribs 165 of locking element 30(which engage suture S after locking element 30 is moved proximally intostepped bore 60 of body 25) and the internal threads 72 disposed on theinterior wall of the proximal section 70 of stepped bore 60 of knotlesssuture anchor 10 creates a secure fit of locking element 30 and suture Swithin body 25, such that tissue can be sufficiently secured to theknotless suture anchor 10 (and hence to bone) without the risk oflocking element 30 or suture S moving within the body 25 of knotlesssuture anchor 10.

As noted above, ribs 165 may have various configurations, eitheridentical to or varied from one another, and/or may be regularly orirregularly spaced.

Thus, while “square-profile” ribs 165 are depicted in FIGS. 22, 24, 28,30-34 and 36, ribs of other profiles and/or geometries (e.g.,“triangle-profile”, helical, threaded, knurling, etc.) also fall withinthe scope of the present invention. See, for example, FIG. 37, whichshows ribs 165 formed with fillets 300.

Furthermore, while ribs 165 are depicted in FIGS. 22, 24, 28, 30-34, 36and 37 as being evenly spaced from one another, it may be desirable tovary the spacing between the ribs, and/or to vary the dimensions of theribs themselves, so as to provide desired characteristics to lockingelement 30 and hence to knotless suture anchor 10. By way of example butnot limitation, the ribs 165 of locking element 30 can have a variableprofile along the length of locking element 30, whereby to provide theknotless suture anchor 10 with variable characteristics along itslength. More particularly, locking element 30 may be formed so that theproximal end of the locking element has fewer ribs 165 than the distalend of the locking element, and/or the ribs 165 at the proximal end ofthe locking element may be spaced farther apart than the ribs 165 at thedistal end of the locking element, and/or the ribs 165 at the proximalend of the locking element may be thinner (in a longitudinal sense) thanthe ribs 165 at the distal end of the locking element (see FIG. 38) suchthat the proximal section of locking element 30 will be “weaker” thanthe distal section of locking element 30. In other words, the ribs 165at the proximal end of locking element 30 can have a profile and/orspacing so as to make those ribs more compliant than the ribs 165 at thedistal end of locking element 30. This will result in the proximalsection of locking element 30 being more easily compressed than thedistal section of locking element 30 or, stated another way, it willresult in the proximal section of locking element 30 providing lessexpansion to the body of knotless suture anchor 10 than the distalsection of locking element 30. This can be desirable in certaincircumstances, since the soft cancellous tissue located in the interiorportion of a bone (i.e., adjacent to the distal end of suture anchor 10)requires greater anchor expansion than the hard cortical tissue locatedat the outer portion of a bone (i.e., adjacent to the proximal end ofthe suture anchor). Hence, by forming locking element 30 so that theribs on the proximal end of the locking element 30 have a highercompliance than the ribs on the distal end of the locking element 30,proximal movement of locking element 30 within the body of the knotlesssuture anchor 10 will cause greater expansion of the anchor bodyadjacent the soft cancellous bone and lesser anchor expansion adjacentthe hard cortical bone. More compliant ribs on the proximal end of thelocking element 30 may also enable locking element 30 to be moreeffective in highly dense bone, where such bone density (and lesscompliant ribs) can combine to prevent proximal movement of the lockingelement. Thus it will be seen that it can be desirable to vary thespacing between ribs 165, and/or to vary the dimensions of the ribsthemselves, so as to provide desired characteristics to locking element30 and hence to knotless suture anchor 10. See, for example, FIGS.39-41, which show additional various spacings between the ribs 165and/or various dimensions for the ribs 165.

In addition, if desired, distal section 145 of bore 140 of lockingelement 30 may be omitted, and bore 140 may open on distal end surface125 of locking element 30, as shown in FIG. 42.

Furthermore, weakened section 132 of locking element 30 may be omittedfrom the proximal end of locking element 30, as shown in FIGS. 43 and44. In place of weakened section 132, an internal chamfer 302 of bore140 prevents a portion of locking element 30 from breaking off when pullrod 35 exits the proximal end of bore 140. This construction can beadvantageous, since when pull rod 35 is drawn through bore 140 oflocking element 30, it pulls through cleanly, with no debris beingcreated.

Also, if desired, the distalmost rib 165 of locking element 30 may betapered, e.g., as shown at 305 in FIG. 44, so as to facilitate passageof locking element 30 into proximal section 70 of stepped bore 60 ofbody 25 of knotless suture anchor 10.

Or, if desired, ribs 165 may be omitted entirely, as shown in FIG. 45.

Still other configurations for locking element 30, including variationsof ribs 165, are shown in FIGS. 46 and 47. FIG. 46 depicts sharper ribs165 to further enhance engagement of suture. FIG. 47 depicts ribs 165with ratchet teeth profiles so as to increase the grip of the ribs onthe suture. More particularly, the suture passing through the sutureanchor is typically secured to soft tissue, and the elasticity of thatsoft tissue tends to draw the suture passing through the suture anchorin a distal direction (i.e., out side opening 90). Therefore, by formingribs 165 of locking element 30 with the structure shown in FIG. 47, thesharp proximal edges of ribs 165 will bear into the suture when thesuture is drawn in the distal direction. As noted above, proximalsection 70 of stepped bore 60 preferably has a textured interior wall soas to facilitate engagement with locking element 30 and a suture Sdisposed between locking element 30 and proximal section 70 of steppedbore 60. In one preferred form of the invention, threads 72 are formedon the inner wall of proximal section 70 of stepped bore 60 (see FIGS.22, 24, 28, 30-34 and 36). However, other surface features may beprovided on the inner wall of proximal section 70 to ensure sufficientsecurement with locking element 30 and suture S, e.g., ribs, knurling,etc.

FIGS. 47A and 47B show another possible construction for locking element30. More particularly, in FIGS. 22, 24, 25, 28, 30-34, 36, 37 and 42,locking element 30 is shown having a weakened section 132 at itsproximal end, wherein the weakened section 132 may be formed by acircumferential groove 133. Alternatively, weakened section 132 oflocking element 30 can be formed by reconfiguring stepped bore 140 sothat it has a long distal section 145 and a short proximal section 150,in the manner shown in FIGS. 47A and 47B. In this form of the invention,when a sufficient proximal force is applied to pull rod 35, weakenedsection 132 of locking element 130 will break away from the remainder oflocking element 30, in the manner shown in FIG. 47B. In this embodiment,locking element 30 travels in a proximal direction within body 25 so asto expand body 25 and lock suture S to knotless suture anchor 10;however, the threshold force of disengaging pull rod 35 from body 25 isthe force at which weakened section 132 of locking element 130 breaksaway from the remainder of locking element 30 (rather than the force atwhich pull rod 35 pulls through bore 140 of locking element 30).

In some cases the suture anchor may be subjected to transverse forces asit is advanced towards, and/or inserted into, the bone hole. This isparticularly true where the suture anchor must be advanced through atight corridor (e.g., such as in arthroscopic surgery), or along atortuous path (e.g., such as when being advanced to a labral repair sitewithin the hip), since in these situations the suture anchor mayaccidentally bump into intervening structures and/or the suture anchormay need to turn along a curved sheath during insertion. When thisoccurs, the suture anchor may be damaged and/or moved out of alignmentwith its inserter, etc., which can result in ineffective anchorplacement in the bone.

Accordingly, in another embodiment of the present invention, and lookingnow at FIGS. 48-59, means are provided to shield and mechanicallysupport knotless suture anchor 10 as it is advanced towards, and/orinserted into, the bone hole. More particularly, in this form of theinvention, inserter 15 comprises a retractable sheath 310 which isco-axial with, and external to, the aforementioned inserter shaft 195.Inserter 15 also comprises an overtube 315. In this form of theinvention, shaft 195 is secured to handle 190 (FIG. 53), retractablesheath 310 is coaxially mounted about shaft 195 and spring-biased in adistal direction by a compression spring 320, and overtube 315 iscoaxially mounted about retractable sheath 310 and secured to handle190. Preferably, when retractable sheath 310 is under the influence ofcompression spring 320, the distal end surface 325 of retractable sheath310 is disposed proximal to the distal end of knotless suture anchor 10,but distal to the proximal end of knotless suture anchor 10 (see FIGS.49 and 51). More preferably, the distal end of retractable sheath 310 islocated between the midpoint of knotless suture anchor 10 and the distalend of knotless suture anchor 10. In this way, retractable sheath 310can cover, and hence protect, the major length of knotless suture anchor10 as the knotless suture anchor is advanced to the surgical site, butstill expose the distal end of knotless suture anchor 10 so as tofacilitate insertion of the knotless suture anchor into a bone hole. SeeFIGS. 48-53. However, when retractable sheath 310 is forced proximally,against the power of compression spring 320, knotless suture anchor 10is completely exposed. See FIGS. 54-59. Preferably retractable sheath310 and overtube 315 have distal markings 326 and 327, respectively,which provide indication of anchor depth. For example, when markings 326and 327 align, the anchor is at the preferred depth. Additionally,retractable sheath 310 preferably has a slot 311 extending from itsdistal end (see FIGS. 51 and 57) to allow suture to pass from withinretractable sheath 310 (i.e., from knotless suture anchor 10 and/orshaft 195) to outside retractable sheath 310. Slot 311 is preferablyrotationally aligned with side opening 90 in knotless suture anchor 10and opening 227 in the side wall of shaft 195.

In use, and looking now at FIGS. 60-63, retractable sheath 310 isinitially disposed in its distal position, i.e., compression spring 320actively pushes the proximal end of retractable sheath 310 away fromhandle 190, so that retractable sheath 310 covers the majority of thelength of knotless suture anchor 10, but leaves the distal tip of theknotless suture anchor 10 exposed for easy locating into a bone hole H.Thereafter, when knotless suture anchor 10 is to be deployed into thebone hole H, the knotless suture anchor 10 is advanced (e.g., through anarthroscopic cannula) to the surgical site, with retractable sheath 310covering, and protecting, the knotless suture anchor 10 during suchadvancement. Overtube 315 prevents retractable sheath 310 fromprematurely retracting while the knotless suture anchor 10 is beingdelivered to the bone site. For example, the knotless suture anchor 10may be passed through a cannula with an elastomeric septum; the septum,being grip-like in nature, will tend to grip the retractable sheath 310and, consequently, retract the retractable sheath, thus removing some orall of the protection it was providing to the knotless suture anchor 10.Overtube 315 provides protection against this occurrence as the septumwill bear against the overtube 315 (it being the outermost surface)instead of retractable sheath 310. Then the exposed distal tip ofknotless suture anchor 10 is placed into bone hole H (FIGS. 60 and 61),with the distal end of retractable sheath 310 contacting the outersurface of the bone B. In this position, retractable sheath 310 contactsthe outer surface of the bone B about the perimeter of the bone hole Hand provides additional mechanical support against any transverse forcesthat may be applied to the knotless suture anchor 10 from the inserter15, for example, if there is a misalignment between the arthroscopicportal and the axis of the bone hole H. The knotless suture anchor 10 isthen advanced into the bone hole H. This is done by moving inserter 15distally. As inserter 15 moves distally, shaft 195 advances the knotlesssuture anchor 10 into the bone hole H while the engagement ofretractable sheath 310 with the outer surface of the bone B causes theretractable sheath 310 to remain stationary relative to the bone B. SeeFIGS. 62 and 63. Under this action, the power of compression spring 320is overcome and the advancing handle 190 moves shaft 195 distally withinretractable sheath 310. In other words, pushing handle 190 distallymoves shaft 195 distally, while compression spring 320 allowsretractable sheath 310 to remain seated on the outer surface of the boneB and retract into the advancing handle 190. During advancement ofknotless suture anchor 10 into the bone hole H, retractable sheath 310continues to provide mechanical support to the knotless suture anchor 10as the knotless suture anchor 10 is pressed further into the bone hole.In this manner, retractable sheath 310 protects and supports knotlesssuture anchor 10 during delivery into the bone hole H.

In a preferred embodiment, retractable sheath 310 and overtube 315 areformed out of biocompatible materials such as stainless steel. In analternative embodiment, retractable sheath 310 is formed out of atransparent polymer. In this embodiment, a distal marking 328 (FIG. 55)on the shaft 195 can be visualized through the transparent retractablesheath 310 to provide visual indication of anchor depth.

In another embodiment, the spring 320 may be sufficiently strong so asto overcome inadvertent retraction of retractable sheath 310 duringdelivery; hence, in this form of the invention, overtube 315 may beomitted.

Alternative Knotless Suture Anchors

In another form of the invention, and looking now at FIGS. 64-66, pullrod 35 may be replaced by a pull suture 330, an enlargement 335 and aconnecting suture 340 connecting pull suture 330 to enlargement 335. Inthis form of the invention, pulling proximally on pull suture 330 causesproximal movement of enlargement 335, whereby to cause proximal movementof locking element 30. As in the preceding constructions, such proximalmovement of locking element 30 causes radial expansion of the body 25 ofknotless suture anchor 10 so as to secure the knotless suture anchor 10to surrounding bone, and captures the suture S within the proximalsection 70 of stepped bore 60, whereby to secure the suture S to theknotless suture anchor (and hence to the bone within which the knotlesssuture anchor 10 is secured). After proximal movement of locking element30, connecting pull suture 330 is detached from connecting suture 340.One or more slits 341 may be formed in the side wall of the anchor body25 so as to weaken the side wall and provide enhanced expansion of theanchor body 25 against adjacent bone. In this form of the invention,locking element 30 preferably comprises an enlargement 342 at its distalend which has a larger diameter than the tapered proximal section 343 ofbore 344. When enlargement 342 of locking element 30 is wedged intotapered proximal section 343 of bore 344, the anchor body 25 expands atslits 341.

In another form of the invention, and looking now at FIGS. 67-69, theconstruction is similar to the construction shown in FIGS. 64-66, exceptthat instead of passing suture S out opening 227 in the side wall ofshaft 195, suture S passes out a second side opening 345 in knotlesssuture anchor 10. Preferably side opening 345 in knotless suture anchor10 is diametrically opposed to side opening 90 in knotless suture anchor10. Suture S may also be passed through the loop of connecting suture340 so that suture S is captured and held secured to the proximal end ofthe locking element during proximal movement of the locking element(i.e., suture S does not get displaced between the locking element 30and anchor body). In addition, if desired, enlargement 335 may extendout the distal end of knotless suture anchor 10. Again, with thisconstruction, pulling proximally on pull suture 330 causes proximalmovement of enlargement 335, whereby to cause proximal movement oflocking element 30. Such proximal movement of locking element 30 causesradial expansion of the body 25 of knotless suture anchor 10 so as tosecure the knotless suture anchor to surrounding bone, and captures thesuture within the proximal section 70 of stepped bore 60, whereby tosecure the suture to the knotless suture anchor (and hence to the bonewithin which the knotless suture anchor is secured).

In still another form of the invention, and looking now at FIGS. 70 and71, locking element 30 is sized to extend out the distal end of knotlesssuture anchor 10, and comprises a crossbore 350 extending therethrough.In this form of the invention, instead of passing suture S through sideopening 90 in knotless suture anchor 10 and out opening 227 in the sidewall of shaft 195 (in the manner of FIGS. 31-34), or through sideopening 90 in knotless suture anchor 10 and out side opening 345 inknotless suture anchor 10 (in the manner of FIGS. 67-69), suture S islooped through crossbore 350 and, when locking element 30 is thereafterpulled proximally to expand suture anchor 10, suture S is pulled intothe distal end of the knotless suture anchor, whereby to bind suture Sto the knotless suture anchor. If desired, locking element 30 may bemoved proximally by a pull rod 355 (which may be connected to lockingelement 30 by a screw connection such as is shown in FIGS. 70 and 71).Thus it will be seen that, with this construction, pulling proximally onpull rod 355 causes proximal movement of locking element 30. Suchproximal movement of locking element 30 causes radial expansion of thebody 25 of knotless suture anchor 10 so as to secure the knotless sutureanchor to surrounding bone, and captures the suture within the distalend of knotless suture anchor 10, whereby to secure the suture to theknotless suture anchor (and hence to the bone within which the knotlesssuture anchor is secured).

In still another form of the invention, and looking now at FIGS. 72-74,locking element 30 comprises a screw adapted to move distally in orderto expand the body of knotless suture anchor 10 and bind suture S to theknotless suture anchor 10. In this form of the invention, lockingelement 30 is stepped at its proximal end and comprises screw threads360 on its exterior surface which cooperate with (i) screw threads 365formed in inserter 15, and (ii) screw threads 370 formed in knotlesssuture anchor 10. The diameter of the screw threads 360 is larger at theproximal section of the locking element 30 than at the distal section ofthe locking element 30 (e.g., the locking element 30 may comprise a#1-72 thread proximally and a #0-72 distally) in order to createexpansion when the proximal section of the locking element reaches theproximal screw threads 370 formed in the knotless suture anchor 10. Notethat in this form of the invention, knotless suture anchor 10 isinitially held to inserter 15 by locking element 30, which spans theinterface of inserter 15 and knotless suture anchor 10 andsimultaneously engages both screw threads 365 in inserter 15 and screwthreads 370 in knotless suture anchor 10. It is important to note that,although locking element 30 comprises two different diameter screwthreads 360, both diameters of screw threads 360 preferably have thesame thread pitch so that distal movement of the locking element doesnot draw the inserter 15 closer to, or move it further away from,knotless suture anchor 10. In addition to the foregoing, knotless sutureanchor 10 comprises a side opening 375 through which suture S passes. Inthis form of the invention, turning locking element 30 (e.g., with adriver 380) causes distal movement of locking element 30. Such distalmovement of locking element 30 causes radial expansion of the body 25 ofknotless suture anchor 10 so as to secure the knotless suture anchor 10to surrounding bone, and captures the suture within the knotless sutureanchor 10, whereby to secure the suture to the knotless suture anchor 10(and hence to the bone within which the knotless suture anchor 10 issecured).

In yet another form of the invention, and looking now at FIGS. 75 and76, the construction is similar to the construction shown in FIGS.72-74, except that locking element 30 is tapered along its entirelength. Again, in this form of the invention, distal movement of lockingelement 30 causes radial expansion of body 25 of knotless suture anchor10 so as to secure the knotless suture anchor to surrounding bone, andcaptures the suture within the interior of the knotless suture anchor,whereby to secure the suture to the knotless suture anchor (and hence tothe bone within which the knotless suture anchor is secured).

In another form of the invention, and looking now at FIGS. 77 and 78,the construction is again generally similar to the construction shown inFIGS. 72-74, except that locking element 30 is straight along its length(i.e., threads 360 are on a constant diameter) and knotless sutureanchor 10 comprises one or more projections 385 which narrow thediameter of the internal bore in the distal section of the knotlesssuture anchor 10. In this form of the invention, distal movement oflocking element 30, which may contain a distal protrusion 387, withinknotless suture anchor 10 causes radial expansion of the body of theknotless suture anchor 10 by engaging projections 385 in the distalsection of the anchor body so as to secure the knotless suture anchor 10to surrounding bone, and captures the suture within the interior of theknotless suture anchor 10, whereby to secure the suture to the knotlesssuture anchor 10 (and hence to the bone within which the knotless sutureanchor 10 is secured).

In still another form of the invention, and looking now at FIGS. 79-81,the construction of knotless suture anchor 10 is generally similar tothe construction shown in FIGS. 72-74, except that locking element 30forms an interference fit with surrounding body of the knotless sutureanchor 10, whereby to expand the body of the knotless suture anchor 10and capture suture S to the body of the knotless suture anchor 10. Inthis form of the invention, locking element 30 may include an inclinedsurface 390 for facilitating the interference fit with suture S, andside opening 375 in body 25 of knotless suture anchor 10 may bediametrically opposed to side opening 90 in body 25 of knotless sutureanchor 10. In this form of the invention, distal movement of lockingelement 30 within knotless suture anchor 10 causes radial expansion ofthe body of the knotless suture anchor 10 so as to secure the knotlesssuture anchor 10 to surrounding bone, and captures the suture within theinterior of the knotless suture anchor 10, whereby to secure the sutureto the knotless suture anchor 10 (and hence to the bone within which theknotless suture anchor is secured).

In yet another form of the invention, and looking now at FIGS. 82 and83, the construction of knotless suture anchor 10 is generally similarto the construction shown in FIGS. 80 and 81, except that when lockingelement 30 is driven distally to expand the body of the knotless sutureanchor and capture suture S to the body of the knotless suture anchor,locking element 30 drives suture S out the distal end of the sutureanchor.

In another form of the invention, and looking now at FIGS. 84-86, theconstruction of knotless suture anchor 10 is similar to the constructionshown in FIGS. 80 and 81, except that locking element 30 includesfingers 395 for piercing suture S as locking element 30 is drivendistally, whereby to enhance fixation of suture S within knotless sutureanchor 10. Preferably, suture S is braided which enables fingers 395 tointerdigitate between the individual fibers of suture S.

In still another form of the invention, and looking now at FIGS. 87-90,the construction of knotless suture anchor 10 is similar to theconstruction shown in FIGS. 79-81, except that locking element 30comprises a slot 400 in its distal end and a slot 405 in its proximalend, with distal slot 400 receiving suture S therein when lockingelement 30 is driven distally, and proximal slot 405 thereafter allowinglocking element 30 to be rotated (e.g., by inserting a driver, notshown, into proximal slot 405), whereby to wind suture S about lockingelement 30 (FIGS. 88-90) and thereby enhance fixation of suture S withinknotless suture anchor 10. Significantly, as suture S is wound aboutlocking element 30, the combined volume of locking element 30 and sutureS increases so as to cause radial expansion of the body of the knotlesssuture anchor, whereby to secure the knotless suture anchor tosurrounding bone.

Use of the Novel Knotless Suture Anchor System for Other TissueRe-Attachment

It should be appreciated that knotless suture anchor system 5 may alsobe used for re-attaching other soft tissue of the hip joint, or forre-attaching tissue of other joints, or for re-attaching tissueelsewhere in the body. In this respect it should be appreciated thatknotless suture anchor system 5 may be used to attach soft tissue tobone or soft tissue to other soft tissue, or for attaching objects(e.g., prostheses) to bone or other tissue.

Modifications of the Preferred Embodiments

It should be understood that many additional changes in the details,materials, steps and arrangements of parts, which have been hereindescribed and illustrated in order to explain the nature of the presentinvention, may be made by those skilled in the art while still remainingwithin the principles and scope of the invention.

What is claimed is:
 1. Apparatus for securing a suture to a bone, theapparatus comprising: an elongated body having a distal end, a proximalend, and a lumen extending between the distal end and the proximal end,the lumen comprising a distal section and a proximal section, the distalsection of the lumen having a wider diameter than the proximal sectionof the lumen; a window extending through the side wall of the elongatedbody and communicating with the lumen, the window being disposed in thevicinity of the intersection between the distal section of the lumen andthe proximal section of the lumen and being sized to receive a suturetherein; an elongated element extending through the lumen of theelongated body, the elongated element comprising a proximal end and adistal end, wherein the elongated element comprises a steppedconfiguration having an enlarged distal section and a reduced proximalsection; and a locking element connected to the distal end of theelongated element and disposed in the distal section of the lumen;whereby, when the elongated body is disposed in a bone, and a sutureextends through the window, and the locking element is thereafter movedproximally, proximal movement of the locking element causes the lockingelement to capture the suture to the elongated body, whereby to securethe suture to the bone; wherein the enlarged distal section of theelongated element is configured to pull through the locking element uponapplication of an appropriate force, whereby to separate the elongatedelement from the locking element before the locking element exits theproximal end of the elongated body.
 2. Apparatus according to claim 1wherein the locking element has a diameter greater than the proximalsection of the lumen, whereby proximal movement of the locking elementcauses the elongated body to expand.
 3. Apparatus according to claim 1wherein the locking element has a diameter approximately equal to theproximal section of the lumen.
 4. Apparatus according to claim 1 whereinthe axis of the locking element is offset from the axis of the elongatedbody.
 5. Apparatus according to claim 1 wherein the suture is attachedto tissue.
 6. Apparatus according to claim 1 wherein the elongated bodycomprises an external flat proximal to, and aligned with, the window. 7.Apparatus according to claim 1 wherein the elongated element comprises arod.
 8. Apparatus according to claim 1 wherein the locking elementcomprises a bore, and further wherein the elongated element is receivedin the bore.
 9. Apparatus according to claim 1 wherein the forcerequired to pull the locking element to capture the suture to theelongated body is less than the force required to pull the lockingelement out of the elongated body.
 10. Apparatus according to claim 1wherein the force required to pull the elongated element out of theelongated body is less than the force required to pull the lockingelement out of the elongated body.
 11. Apparatus according to claim 1wherein the locking element comprises a weakened section at its proximalend, and further wherein the weakened section is configured to breakaway from the remainder of the locking element when the enlarged distalsection of the elongated element pulls through the locking element. 12.Apparatus according to claim 1 wherein the outside of the lockingelement comprises a plurality of ribs.
 13. Apparatus according to claim1 further comprising an inserter for manipulating the elongated body,wherein the inserter comprises a hollow tube having a lumen extendingtherethrough, wherein the lumen of the hollow tube communicates with thelumen of the elongated body, and further wherein the elongated elementextends through the lumen of the hollow tube.
 14. Apparatus according toclaim 13 wherein the proximal end of the elongated element terminates inthe inserter.
 15. Apparatus according to claim 13 wherein the hollowtube comprises a window extending through the side wall of the hollowtube and communicating with the lumen of the hollow tube, the windowbeing sized to receive a suture therein.
 16. Apparatus according toclaim 13 wherein the elongated body is held to the inserter by applyingproximally-directed tension to the elongated element.
 17. Apparatusaccording to claim 1 wherein the locking element comprises a steppedbore having an enlarged distal section and a reduced proximal section,and further wherein the enlarged distal section of the elongated elementis sized to be received in the enlarged distal section of the lockingelement, and the reduced proximal section of the elongated element issized to be received in the reduced proximal section of the lockingelement.
 18. Apparatus according to claim 17 wherein the enlarged distalsection of the elongated element has a larger diameter than the reducedproximal section of the locking element.
 19. A method for securing asuture to a bone, the method comprising: providing apparatus comprising:an elongated body having a distal end, a proximal end, and a lumenextending between the distal end and the proximal end, the lumencomprising a distal section and a proximal section, the distal sectionof the lumen having a wider diameter than the proximal section of thelumen; a window extending through the side wall of the elongated bodyand communicating with the lumen, the window being disposed in thevicinity of the intersection between the distal section of the lumen andthe proximal section of the lumen and being sized to receive a suturetherein; an elongated element extending through the lumen of theelongated body, the elongated element comprising a proximal end and adistal end, wherein the elongated element comprises a steppedconfiguration having an enlarged distal section and a reduced proximalsection; and a locking element connected to the distal end of theelongated element and disposed in the distal section of the lumen;extending the suture through the window; positioning the elongated bodyin the bone; and moving the locking element proximally, such thatproximal movement of the locking element causes the locking element tocapture the suture to the elongated body, whereby to secure the sutureto the bone; wherein the enlarged distal section of the elongatedelement is configured to pull through the locking element uponapplication of an appropriate force, whereby to separate the elongatedelement from the locking element before the locking element exits theproximal end of the elongated body.
 20. A method according to claim 19wherein proximal movement of the locking element expands the elongatedbody against the bone.
 21. Apparatus for securing a suture to a bone,the apparatus comprising: an elongated body having a distal end, aproximal end, and a lumen extending between the distal end and theproximal end, the lumen comprising a distal section and a proximalsection, the distal section of the lumen having a wider diameter thanthe proximal section of the lumen; a window extending through the sidewall of the elongated body and communicating with the lumen, the windowbeing disposed in the vicinity of the intersection between the distalsection of the lumen and the proximal section of the lumen and beingsized to receive a suture therein; an elongated element extendingthrough the lumen of the elongated body, the elongated elementcomprising a proximal end and a distal end, wherein the elongatedelement comprises a stepped configuration having an enlarged distalsection and a reduced proximal section; and a locking element connectedto the distal end of the elongated element and disposed in the distalsection of the lumen; whereby, when the elongated body is disposed in abone, and a suture extends through the window, and the locking elementis thereafter moved proximally, proximal movement of the locking elementcauses the locking element to capture the suture to the elongated body,whereby to secure the suture to the bone; wherein the elongated elementis configured to disconnect from the locking element before the lockingelement exits the proximal end of the elongated body; wherein thelocking element comprises a stepped bore having an enlarged distalsection and a reduced proximal section, and further wherein the enlargeddistal section of the elongated element is sized to be received in theenlarged distal section of the locking element, and the reduced proximalsection of the elongated element is sized to be received in the reducedproximal section of the locking element.
 22. Apparatus according toclaim 21 wherein the enlarged distal section of the elongated elementhas a larger diameter than the reduced proximal section of the lockingelement.
 23. Apparatus for securing a suture to a bone, the apparatuscomprising: an elongated body having a distal end, a proximal end, and alumen extending between the distal end and the proximal end, the lumencomprising a distal section and a proximal section, the distal sectionof the lumen having a wider diameter than the proximal section of thelumen; an elongated element extending through the lumen of the elongatedbody, the elongated element comprising a proximal end and a distal end,wherein the elongated element comprises a stepped configuration havingan enlarged distal section and a reduced proximal section; and a lockingelement connected to the distal end of the elongated element anddisposed in the distal section of the lumen; whereby, when the elongatedbody is disposed in a bone, and a suture extends through at least aportion of the lumen of the elongated body, and the locking element isthereafter moved proximally, proximal movement of the locking elementcauses the locking element to capture the suture to the elongated body,whereby to secure the suture to the bone; wherein the enlarged distalsection of the elongated element is configured to pull through thelocking element upon application of an appropriate force, whereby toseparate the elongated element from the locking element after thelocking element captures the suture to the elongated body.
 24. Apparatusaccording to claim 23 wherein the locking element has a diameter greaterthan the proximal section of the lumen, whereby proximal movement of thelocking element causes the elongated body to expand.
 25. Apparatusaccording to claim 23 wherein the locking element has a diameterapproximately equal to the proximal section of the lumen.
 26. Apparatusaccording to claim 23 wherein the axis of the locking element is offsetfrom the axis of the elongated body.
 27. Apparatus according to claim 23wherein the suture is attached to tissue.
 28. Apparatus according toclaim 23 wherein the elongated element comprises a rod.
 29. Apparatusaccording to claim 23 wherein the locking element comprises a bore, andfurther wherein the elongated element is received in the bore. 30.Apparatus according to claim 23 wherein the force required to pull thelocking element to capture the suture to the elongated body is less thanthe force required to pull the locking element out of the elongatedbody.
 31. Apparatus according to claim 23 wherein the force required topull the elongated element out of the elongated body is less than theforce required to pull the locking element out of the elongated body.32. Apparatus according to claim 23 wherein the locking elementcomprises a weakened section at its proximal end, and further whereinthe weakened section is configured to break away from the remainder ofthe locking element when the enlarged distal section of the elongatedelement pulls through the locking element.
 33. Apparatus according toclaim 23 wherein the outside of the locking element comprises aplurality of ribs.
 34. Apparatus according to claim 23 furthercomprising an inserter for manipulating the elongated body, wherein theinserter comprises a hollow tube having a lumen extending therethrough,wherein the lumen of the hollow tube communicates with the lumen of theelongated body, and further wherein the elongated element extendsthrough the lumen of the hollow tube.
 35. Apparatus according to claim34 wherein the proximal end of the elongated element terminates in theinserter.
 36. Apparatus according to claim 34 wherein the hollow tubecomprises a window extending through the side wall of the hollow tubeand communicating with the lumen of the hollow tube, the window beingsized to receive a suture therein.
 37. Apparatus according to claim 34wherein the elongated body is held to the inserter by applyingproximally-directed tension to the elongated element.
 38. Apparatusaccording to claim 23 wherein the locking element comprises a steppedbore having an enlarged distal section and a reduced proximal section,and further wherein the enlarged distal section of the elongated elementis sized to be received in the enlarged distal section of the lockingelement, and the reduced proximal section of the elongated element issized to be received in the reduced proximal section of the lockingelement.
 39. Apparatus according to claim 38 wherein the enlarged distalsection of the elongated element has a larger diameter than the reducedproximal section of the locking element.
 40. A method for securing asuture to a bone, the method comprising: providing apparatus comprising:an elongated body having a distal end, a proximal end, and a lumenextending between the distal end and the proximal end, the lumencomprising a distal section and a proximal section, the distal sectionof the lumen having a wider diameter than the proximal section of thelumen; an elongated element extending through the lumen of the elongatedbody, the elongated element comprising a proximal end and a distal end,wherein the elongated element comprises a stepped configuration havingan enlarged distal section and a reduced proximal section; and a lockingelement connected to the distal end of the elongated element anddisposed in the distal section of the lumen; extending the suturethrough at least a portion of the lumen of the elongated body;positioning the elongated body in the bone; moving the locking elementproximally, such that proximal movement of the locking element causesthe locking element to capture the suture to the elongated body, wherebyto secure the suture to the bone; and applying an appropriate force topull the enlarged distal section of the elongated element through thelocking element, whereby to separate the elongated element from thelocking element after the locking element captures the suture to theelongated body.
 41. A method according to claim 40 wherein the lockingelement has a diameter approximately equal to the proximal section ofthe lumen.
 42. A method according to claim 40 wherein the elongatedelement comprises a rod.
 43. A method according to claim 40 wherein thelocking element comprises a stepped bore having an enlarged distalsection and a reduced proximal section, wherein the enlarged distalsection of the elongated element is sized to be received in the enlargeddistal section of the locking element, and the reduced proximal sectionof the elongated element is sized to be received in the reduced proximalsection of the locking element, and further wherein the enlarged distalsection of the elongated element has a larger diameter than the reducedproximal section of the locking element.
 44. A method according to claim40 wherein the force required to pull the locking element to capture thesuture to the elongated body is less than the force required to pull thelocking element out of the elongated body.
 45. A method according toclaim 40 wherein the force required to pull the elongated element out ofthe elongated body is less than the force required to pull the lockingelement out of the elongated body.